A projector is one of image projection devices and refers to an electronic device capable of enlarging and projecting, for example, a photograph, a picture, or a character on a slide or a transparent sheet through a lens. Due to the development of techniques, a recent projector may output an image or a video in a file format as an image on a screen. That is, the projector may output an image so as to show the output image to many people. For example, the projector may be usefully used when conducting a seminar or a meeting. The projector is generally classified as a Cathode Ray Tube (CRT) projector, a Liquid Crystal Display (LCD) projector, or a Digital Light Processing (DLP) projector, depending on techniques of generating an image. The CRT projector is a system that amplifies an image signal from an external appliance in a cathode-ray tube (CRT) and projects the amplified image signal through a projection lens so that an image is produced on a screen. The CRT projector is also referred to as a PRT projector or a beam projector. The CRT projector employs a principle which is the same as that of an existing CRT TV. The CRT projector is advantageous in that it can provide the clearest image quality. However, the CRT projector is disadvantageous in that its brightness is limited and it is difficult to install and to perform convergence correction. Due to the disadvantages, the use of CRT projectors has gradually declined. The LCD projector refers to a projector that passes lights generated from a lamp through a transmission type LCD panel to be collected as one image, and projects the image to be formed on a screen. The LCD projector is currently widely used since it is compact and light compared to the CRT projector, and gives high performance for its money. However, the LCD projector may be poor in the reproducibility of natural colors compared to the CRT projector. The DLP projector refers to a projector that passes lights generated from a lamp through a wheel to reflect an image to a Digital Micro Device (DMD) chip, and enlarges and projects the reflected image. The DMD chip is configured such that fine mirrors are switched thousands of times, or more, to selectively reflect light or not so that a high resolution and high definition image can be implemented. The DLP projector is controlled in a fully digitized manner. Thus, the DLP projector exhibits high utilization efficiency of light compared to the CRT projector and the LCD projector which are analog systems so that the DLP projector may be excellent in the quality of an image projected at the same brightness and color reproducibility. DLP projectors have not been popular due to high initial prices and high maintenance costs thereof. However, as the prices of DMD chips have declined, the prices of DLP projectors also have declined and the demand for the DLP projectors increases.